Considerable efforts have been expended to develop coating compositions with improved performance (both protective and aesthetic) properties. Polyurea coatings have been among the coatings commercially applied to various substrates to provide protection to the substrates and to improve properties of the substrates. Polyurea compositions have been used as protective coatings in industrial applications for coating of process equipment to provide corrosion resistance or as caulks and sealants in a variety of aggressive environments.
However, certain prior art polyurea coatings have been known to have deficiencies that inhibit their effectiveness in providing adequate protection to the substrate or to improve properties of the substrate. For example, known polyurea coating compositions may have relatively high viscosity that inhibits flow over the substrate or other underlying coating compositions. They may also have limited pot-life due to the high level of reactivity between the isocyanate component and the amine component. Also, certain polyurea coating compositions may have poor adhesion properties to a previously applied coating or to the substrate itself and/or exhibit poor durability upon prolonged exposure to ultraviolet radiation and/or humidity conditions.
Accordingly, it is desirable to provide polyurea coating compositions that may enhance adhesion to previously applied coatings or to the substrate, and/or have a relatively lower viscosity that improves the flowable state of the coating composition for a longer period of time.